Fitment having removable membrane

ABSTRACT

A fitment for use as a pour spout for a paper carton or flexible bag for liquids and powders has a flange which may be welded around a hole in the carton or bag. A spout projecting outward from the flange is provided with a removable membrane integral with the interior of the spout. Preferably the membrane is concave. A horizontally disposed pull ring is attached to the membrane by a connector so that pulling the ring removes the membrane by fracturing the tear line at the juncture of the outer edge of the membrane and the projection. A cap snaps over the spout and may be removed by unscrewing the complementary threads on cap and spout. Optionally, a tamper-evidencing band frangibly connected to the lower edge of the cap skirt engages the exterior of the spout so that the cap cannot be removed without breaking the frangible connection. Various means for detachably securing the fitment to a spud during delivery of the fitment from a chute to the interior of a carton are disclosed. In one modification, the membrane is located approximately midway of the height of the fitment spout. The spud is inserted into the spout below the membrane. In other modifications the membrane is near the bottom of the spout and there are downward projections of the fitment which engage the exterior or interior of the spud. The downward projection may be in the form of a ring, preferably interrupted, or fingers or a stud. The ring or fingers or stud may be on the flange or the membrane. In another modification, when the cap is removed, the flexible post connecting the pull ring to the membrane straightens, popping the ring outward so that it may conveniently be gripped. In still another modification, a curvilinear score line is formed in the membrane intersects the line of weakness and the connector is attached at the intersection.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of application, Ser. No. 08/808,682, filed Feb. 28, 1997, now U.S. Pat. No. ______ , which is a continuation of application Ser. No. 08/380,832, filed Jan. 30, 1995, now abandoned.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to a new and improved fitment having a removable membrane which closes off the interior of the fitment spout More particularly, the invention relates to a fitment which fits around a hole in a panel of a paperboard carton or other container, used for packaging liquids and powders.

[0004] 2. Description of Related Art

[0005] Fitments having membranes are shown in such patents as U.S. Pat. No. 5,303,838, issued Apr. 19, 1994, and particularly FIGS. 14-16 thereof. Other patents showing membranes are U.S. Pat. No. 3,458,080, issued Jul. 29, 1969, U.S. Pat. No. 4,380,303, issued Apr. 19, 1983, and others. The present invention is an improvement on the prior art in that in some modifications of the invention the membrane is located approximately midway of the height of the spout.

[0006] Other fitments are moved from a chute or other source to the interior of a carton by a spud which is attached to the fitment by vacuum. The present invention eliminates the use of vacuum and the mechanical problems inherent therein.

SUMMARY OF THE INVENTION

[0007] The fitment of the present invention comprises a spout portion having a peripheral flange which may be welded or otherwise attached to a panel of a paperboard carton or to a flexible plastic container. A spout projects upward from the flange and, in the preferred embodiments, is externally threaded adjacent its upper end. In some modifications of the invention, positioned within the spout is an internal membrane which may be concave and is joined to an inward projection of the spout along a line of weakness. A pull tab, such as a ring, is connected to the membrane in such fashion that by pulling the pull tab the membrane is detached from the inward projection of the spout. The concave membrane facilitates the consumer gripping the ring and has certain advantages in molding the part.

[0008] The cap of the present invention has a skirt which is internally threaded to engage the threads of the spout. A lower portion of the cap may have a tear band having a bead which snaps under a shoulder on the lower portion of the spout. The tear band may be connected to the upper portion of the skirt by frangible means so that the cap may not be removed without giving external evidence of tampering.

[0009] One of the features of the invention is the fact that the cap may be attached to the spout by pressing the cap downward relative to the spout, the mating threads on the spout and cap skirt slipping past each other and then interengaging. The tamper-evident band has a bead which engages a shoulder on the spout so that the cap cannot be unscrewed without severing the bridges which connect the band to the skirt and giving evidence of tampering.

[0010] The tear band not only provides tamper-evidencing in addition to the membrane being intact, it also is an anti-back-off feature to keep the cap from unscrewing during initial distribution.

[0011] A particular object and advantage of the present invention is that the fitment is so constructed that, by means of a spud of a mandrel, it may be moved from a chute or other storage location to the carton. In preferred embodiments the mandrel is moved to place the fitment inside the carton and maneuvered so that the spout fits through and extends outside a hole in a wall of the carton. In the prior art, the fitment has been held on the spud by vacuum. This method is undesirable in that a source of vacuum must be provided and, further, drawing the vacuum to a sufficient extent to hold the fitment on the stud is time consuming, as is release of the vacuum.

[0012] One means for attachment to the spud is to locate the membrane which seals the spout above the lower end of the spout a sufficient distance for the spud to enter the lower end of the fitment. One means for holding the fitment on the spud is to provide an internal bead near the bottom of the spout which frictionally engages the spud. In a modification of the present invention, such a bead is intermittent rather than continuous. In another version of the invention, vertical internal ribs are formed on the lower end of the spout to grip the spud.

[0013] In another modification of the invention, the membrane, if desired, may be positioned at or adjacent the lower end of the spout. A ring depending from fitment engages the exterior of the spud. Optionally, instead of a continuous ring, fingers may project below the flange engaging the exterior of the spud. Such fingers may be rectangular in cross section or hooked. In a further modification, the ring or fingers may engage a groove formed in the spud.

[0014] Another optional feature of the invention is to form the connector or post between the pull tab and the membrane of a resilient material and make it longer than the distance between the membrane and the upper end of the spout. With a cap applied to the spout, the pull tab bears against the underside of the top of the cap. When the cap is removed, the post straightens so that the pull tab pops above the upper edge of the spout, where it may be conveniently gripped by the consumer.

[0015] In a still further modification of the invention, a curvilinear tear line is formed on the membrane either on the top or bottom surface thereof which intersects the line of weakness between the membrane and the interior of the spout. The post connecting the membrane to the pull tab is preferably located at the intersection of the curvilinear line and the line of weakness. By pulling the pull tab, the membrane tears at the curvilinear line and also tears at the line of weakness, faciliating removal of the membrane.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention:

[0017]FIG. 1 is a vertical sectional view through the cap and one form of spout in assembled condition.

[0018]FIG. 2 is a side elevational view of the spout of FIG. 1.

[0019]FIG. 3 is a top plan view of the spout of FIG. 1.

[0020]FIG. 4 is a vertical sectional view taken substantially along the line 4-4 of FIG. 3.

[0021]FIG. 5 is a schematic view showing how the fitment may be temporarily attached to the spud of an anvil of a machine for inserting the fitment into a panel of a carton.

[0022]FIG. 6 is a view similar to FIG. 4 showing a modification.

[0023]FIG. 6A is an enlarged fragmentary perspective view of a portion of FIG. 6.

[0024]FIG. 7 is a bottom plan view of the structure of FIG. 6.

[0025]FIG. 8 is a view similar to FIG. 4 of a further modification.

[0026]FIG. 9 is a bottom plan view of the structure of FIG. 8.

[0027]FIG. 10 is a view similar to FIG. 1 of a further modification.

[0028]FIG. 11 illustrates the structure of FIG. 10 with the cap removed.

[0029]FIG. 12 is a bottom plan view of the structure of FIG. 10.

[0030]FIG. 13 is a view similar to FIG. 1 of another modification.

[0031]FIG. 14 is a bottom plan view of the modification of FIG. 13.

[0032]FIG. 15 is a fragmentary view showing a further modification of FIG. 13.

[0033]FIG. 16 is a fragmentary sectional view of a spud used with the modifications of, for example, FIGS. 13 and 17.

[0034]FIG. 17 is a view similar to FIG. 13 of a modification.

[0035]FIG. 18 is a bottom plan view of the modification of FIG. 17.

[0036]FIG. 19 is a view similar to FIG. 13 of a still further modification.

[0037]FIG. 20 is a view similar to FIG. 5 of another modification.

[0038]FIG. 21 is a view similar to FIG. 5 of still another modification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to those embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims.

[0040] One environment in which the present invention may be employed is by attachment to a carton panel 11 having a hole 12 therein. Fitment 16 is provided with a flange 17 which is welded or otherwise attached to the underside of panel 11 surrounding hole 12. Projecting up from the inner edge of flange 17 there may be a step 18 having an outside dimension to fit within the hole 12 and having a height approximately equal to the thickness of panel 11. Above step 18, the fitment has an inward extending portion 19. Extending upward from the inner edge of portion 19 is lower spout stretch 21 and thereabove is an upward-inward extending slanted stretch 22 which merges into a vertically extending upper stretch 23 terminating in a top edge 24. The inner and outer surfaces of the spout may be termed the “inner wall surface” and “outer wall surface”, respectively.

[0041] Formed on the inside of the lower portion of lower spout stretch 21 is an inward-downward slanted bead 26 having a purpose which hereinafter appears.

[0042] An external shoulder 27 is formed at the juncture of lower spout stretch 21 and slanted stretch 22 for the purpose of attachment to the tamper-evidencing band of the cap as hereinafter explained. On the interior of the spout at approximately the juncture of the slanted stretch 22 and the upper stretch 23 is an inward projection 29 having an upper inner corner 31. The underside of projection 29 and its juncture with lower spout stretch 21 is a curved surface 30 which facilitates dispensing the contents of the container. Projection 29 is positioned upward from the bottom of the spout. On the exterior of upper spout stretch 23 are external threads 28, here shown as eight in number, of an arcuate length of approximately 270°.

[0043] Above and inward of corner 31 is membrane 32 molded integrally with the fitment 16. The central portion of membrane 32 may be concave as shown by reference numeral 33. The lower outer edge 34 of membrane 32 joins the upper inner corner 31 of projection 29 and the connection therebetween is thin and constitutes a line of weakness or tear line 36. At one portion of member 32 is an upward connection or post 37 reinforced by thin vertical gusset 38 and connected to horizontal pull ring 39 which is located below the level of top edge 24. When the user grips ring 39 and pulls upward, the tear line 36 breaks and the membrane 32 may be removed.

[0044] Cap 46 used with fitment 16 has a top 47 from which depends an upper skirt 48 joined to top 47 by a downwardly rounded corner 49. On the exterior of upper skirt 48 are vertical ribs 51 which assist the user in unscrewing the cap from the fitment. Upper skirt 48 is provided with internal threads 52 mating with the external threads 28 of fitment 16. The shape of the threads is such that when the cap 46 is pressed vertically downwardly on fitment 16, the threads 52 slip over threads 28 and interengage.

[0045] In the form of the invention shown in FIG. 1, a hollow plug 53 is formed on the underside of top 57, the lower outer corner thereof having a curved edge 54 which engages the inside of upper fitment 23 in a liquid tight seal.

[0046] Optionally, a tamper evident band 56 is integrally attached to the bottom of upper skirt 48 by means of 8 angularly-spaced frangible bridge connections 61, it being understood that the number and placement of such connections is subject to variation. Band 56 is provided with an internal bead 57 which snaps under shoulder 27 when the cap is applied to the fitment. To facilitate engagement of shoulder 27, an internal groove 58 is formed in band 56 immediately above internal bead 57.

[0047] Directing attention to FIG. 5, automatic equipment for welding the fitment flange 17 to the underside of panel 11 is known in the art. In one form of such equipment an anvil or mandrel 71 has a flange 72 to which is attached a spud 73 which picks the fitment off of a chute (not shown) by fitting inside the lower spout stretch 21. The lowest portion of the concave area 33 of membrane 32 is above the upper edge of spud 73. In the form of the invention shown in FIG. 5, spud 73 has an external diameter such that when it is inserted through the lower end of the fitment 16 the inner bead 26 frictionally engages the exterior of spud 73. The spud is formed with a concavity 74 so as not to conflict with the concavity 33 of membrane 32. Holes 76 in spud 73 relieve any vacuum which might tend to impede release of fitment 16 from spud 73 when the fitment has been positioned in the carton panel 11, as shown in FIG. 1.

[0048] As shown in FIGS. 6 and 7, inner bead 26 need not be continuous. Bead 26 a is interrupted, there being gaps 81 between segments 82. The number and placement of gaps 81 is subject to variation. The structure shown makes the bead 26 a more flexible when engaging spud 76. Further the gaps 81 make it possible to pour out the contents of the carton more completely. As shown in FIG. 6A the upper surfaces of segments 82 slope downward-inward to facilitate engagement with spud 73.

[0049]FIGS. 8 and 9 illustrate a construction wherein the bead 26 is eliminated. Vertical internal ribs 84 are formed extending upward from adjacent the bottom edge of lower spout stretch 21 b. Such ribs 84 engage the exterior of spud 73 to detachably secure the fitment 16 b on the anvil 71. The number, width, thickness, and length of ribs 84 is subject to variation. Preferably the lower ends of ribs 84 are formed with downward-outward beveled surfaces 85 to facilitate the ribs 84 slipping over the spud.

[0050]FIGS. 10 and 11 illustrate a still further modification. The connector or post 37 c is elongated and resilient. Pull tab 39 c bears against the underside of top 47 c of cap 46 c. As shown in FIG. 11, when the cap 46 c is removed, post 37 c straightens and tab 39 c assumes a position above the top edge 24 c of the upper stretch 23 c of the spout. Accordingly, tab 39 c is more easily gripped by the consumer.

[0051] The modification of FIG. 12 is shown applied to the modification of FIGS. 10 and 11. However, it could be incorporated in any of the other modification. FIG. 12 shows a modified membrane 32 c having a curvilinear groove 86 formed on the upper surface or the underneath surface thereof. The post or connector 37 c connects tab 39 c to the membrane 32 c adjacent the intersection of groove 86 with the tearline or line of weakness 36 c. The groove 86 is similar to the groove denominated “51” in U.S. Pat. No. 5,303,834, FIGS. 9-17.

[0052] Directing attention to FIG. 13, it will be seen that the membrane 32 e may be located at the bottom edge of lower spout stretch 21 e or at any desired location above said bottom edge. Attachment to spud 73 of anvil 71 shown in FIG. 16 is accomplished by means of downward extending fingers 91 on the lower surface or of inward extending portion 19 e. The fingers 91 fit into groove 92 in spud 7 e to detachably secure the fitment 16 e there. Step 96 of spud 73 e accommodates flange 17 e being lower than portion 19 e. The number of fingers 91, spacing therebetween and length thereof is subject to variation. It will be understood that fingers 91 might be formed on flange 17 e. It is desirable that fingers 91 be used, rather than a continuous ring in order to facilitate dispensing all the contents of the container.

[0053]FIG. 15 illustrates that in cross section the fingers 91 f may be hooked.

[0054]FIG. 17-18 illustrate a modification of FIGS. 13-14 where the fingers 91 are replaced by a ring 93 which fits into the groove 92 of spud 73 e of FIG. 16. Although shown as continuous, ring 93 may be formed with an opening (not shown) to facilitate complete dispensing of the contents of the container.

[0055]FIG. 19 is a view similar to FIG. 17 in which ring 93 h depends from membrane 32 h. It will be understood that the groove (not shown) in the spud (not shown) which engages ring 93 h is suitably positioned and dimensioned for such purpose. It will further understood that the position of membrane 32 h relative to the height of spout stretch 21 h is also subject to variation.

[0056]FIG. 20 shows a stud 97 depending from membrane 32 j. Stud 97 is received in bore 98 formed in boss 99 in the upper surface of spud 73 j or of a mandrel. Stud 97 frictionally engages bore 98 as the fitment is transported from a chute or other source to the carton.

[0057]FIG. 21 illustrates a reinforcing ring 101 on or near the periphery of flange 17 k which depends below flange 17 k. Preferably openings 102 are formed at one or more locations around ring 101 to facilitate dispensing all the contents of the container. Spud 73 k may be modified to engage ring 101. Thus an outer ring 106 of greater inside diameter than the outside diameter of ring 101 and preferably formed with an internal upward-outward taper 107 projects above spud 73 k and engages the outside of ring 106. Inner ring 104 having an outside diameter less than that of the inside diameter of ring 101 also projects above spud or mandrel 73 k. Groove 96 between rings 103 and 104 frictionally engages ring 101.

[0058] In other respects, the modifications of FIGS. 6-7, 8-9, 10-12, 13-14, 15, 17-18, 19, 20, & 21 resemble those of the preceding modifications and the same reference numerals followed by the subscripts a, b, c, e, f, g, h, j, and k respectively indicate corresponding parts.

[0059] For purpose of convenience, as used in the accompanying claims, “upper”, “lower”, “upward”, “downward”, “above”, and “below” refer to the position of the fitment shown in the accompanying drawings. It will be understood that during manufacture, attachment and use, the parts may be positioned in other orientations.

[0060] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

What is claimed is:
 1. In combination, a spud having a fitment-engaging surface and a fitment, said fitment comprising, a spout flange, a spout projecting upward from said flange having an upper and a lower end and an inner and an outer wall surface, a membrane sealing off said spout having a peripheral edge joined to said inner wall surface along a line of weakness, said fitment being dimensioned to detachably engage said fitment-engaging surface of said spud by friction when said spud is applied to said lower end to prevent unintentional disengagement of said spud from said fitment.
 2. The combination of claim 1 in which said line of weakness is spaced upward from said lower end and said spout is unobstructed from said lower end up to said line of weakness.
 3. The combination of claim 1 in which said inner wall surface is dimensioned to detachably engage said fitment engaging surface.
 4. The combination of claim 3 in which further comprises an internal bead in said inner wall surface, said bead detachably engaging said fitment-engaging surface when said spud is inserted into said lower end.
 5. The combination of claim 4 in which said bead is interrupted with gaps between segments of said bead.
 6. The combination of claim 3 which further comprises internal ribs on said inner wall surface, said ribs detachably engaging said fitment-engaging surface when said spud is inserted into said lower end.
 7. The combination of claim 1 in which further comprises a member depending from fitment, said spud being formed with a groove to receive said membrane.
 8. The combination of claim 7 in which said member is a ring.
 9. The combination of claim 8 in which said ring depends from said flange.
 10. The combination of claim 8 in which said ring depends from said membrane.
 11. The combination of claim 10 in which said ring is hooked in cross-sectional.
 12. The combination of claim 8 in which said ring is interrupted.
 13. The combination of claim 7 in which said member comprises a plurality of vertically disposed fingers.
 14. The combination of claim 13 in which said fingers are hooked.
 15. The combination of claim 7 in which said member comprises a stud depending from said membrane.
 16. The combination of claim 7 in which said member comprises a ring depending from the periphery of said flange.
 17. In combination, a fitment and a cap, said fitment comprising a spout having an upper and a lower end and an inner and an outer wall surface, a membrane sealing off said spout joined to said inner wall surface along a line of weakness, a pull tab, a connector connecting said pull tab to said membrane, said connector being flexible, cap engaging means on said fitment, said cap comprising a top and a depending skirt, fitment engaging means on said cap cooperable with said cap engaging means to detachably secure said cap on said fitment, said pull tab bearing against said top when said cap is on said spout and said connector is flexed, said connector straightening and said pull tab extending at least partially above said upper end when said cap is removed from said spout, said membrane detaching at least partially from said inner wall surface when said pull tab is pulled.
 18. The combination of claim 17 in which said connector bends when said cap is in position on said spout.
 19. The combination of claim 17 in which said cap engaging means and said fitment engaging means comprise mating threads.
 20. A fitment comprising an annular spout flange, a spout projecting upward from said flange having an upper end a lower end and an inner and an outer wall surface, a membrane integral with said spout sealing off said spout, said membrane having a peripheral edge joined to said inner wall surface along a circumferential line of weakness, said membrane being formed with a serpentine groove extending from a point on said line of weakness inward of said membrane to a terminus remote from said point, a connector integral with said membrane extending from said point toward said upper end, and a pull tab connected to said connector at a point remote from said point, said membrane fracturing both on said line of weakness and said serpentine groove when said pull tab is pulled.
 21. A fitment according to claim 20 in which said inner wall is formed with an inward projection and said peripheral edge is joined to said projection.
 22. A fitment according to claim 21 in which said projection has an upper inner first corner and said edge of said membrane has an outer lower second corner, said second corner being disposed above and inward of said first corner and joined thereto at said line of weakness.
 23. A fitment according to claim 20 in which said pull tab is integral with said connector.
 24. A fitment for use with a spud having a fitment-engaging surface, said fitment comprising, a spout flange, a spout projecting upward from said flange having an upper and a lower end and an inner and an outer wall surface, a membrane sealing off said spout having a peripheral edge joined to said inner wall surface along a line of weakness, said fitment being dimensioned to detachably engage said fitment-engaging surface of said spud by friction when said spud is applied to said lower end to prevent unintentional disengagement of said spud from said fitment.
 25. A fitment according to claim 24 in which said line of weakness is spaced upward from said lower end and said spout is unobstructed from said lower end up to said line of weakness.
 26. A fitment according to claim 24 in which said inner wall surface is dimensioned to detachably engage said fitment-engaging surface.
 27. A fitment according to claim 26 which further comprises an internal bead on said inner wall surface, said bead being shaped to detachably engage the fitment-engaging surface when the spud is inserted into said lower end.
 28. A fitment according to claim 27 in which said bead is interrupted with gaps between segments of said bead.
 29. A fitment according to claim 26 which further comprises internal ribs on said inner wall surface, said ribs being shaped to detachably engage the fitment-engaging surface when the spud is inserted into said lower end.
 30. A fitment according to claim 24 which further comprises a member depending from fitment.
 31. A fitment according to claim 30 in which said member is a ring.
 32. A fitment according to claim 31 in which said ring depends from said flange.
 33. A fitment according to claim 31 in which said ring depends from said membrane.
 34. A fitment according to claim 33 in which said ring is hooked in cross-section.
 35. A fitment according to claim 31 in which said ring is interrupted.
 36. A fitment according to claim 30 in which said member comprises a plurality of vertical disposed fingers.
 37. A fitment according to claim 36 in which said fingers are hooked.
 38. A fitment according to claim 30 in which said member comprises a stud depending from said membrane.
 39. A fitment according to claim 30 in which said member comprises a ring depending from the periphery of said flange.
 40. A fitment according to claim 24 in which said membrane is located adjacent said lower end.
 41. A method of transporting a fitment from a first station to a second station, comprising providing a fitment according to claim 24 , at said first station, said fitment having a spud-engaging portion, providing a container having an apertured wall at said second station, providing a spud having a fitment-engaging portion, frictionally engaging said spud engaging portion with said fitment engaging portion at said first station, moving said spud and fitment thereon from said first station to said second station, fitting said fitment inside said container at said second station and disengaging said spud from said fitment.
 42. A method according to claim 41 in which said membrane is spaced upward from said lower end, said spud entering said lower end to frictionally engage said inner wall surface.
 43. A method according to claim 41 in which said inner wall surface is dimensioned to detachably engage said fitment-engaging surface.
 44. A method according to claim 43 in which said spud engaging portion comprises an internal bead on said inner wall surface below said membrane to engage said fitment-engaging portion.
 45. A method according to claim 44 in which said bead is interrupted.
 46. A method according to claim 43 in which said inner wall surface is formed with internal ribs on said inner wall surface engaging said fitment-engaging portion.
 47. A method according to claim 41 in which said spud engaging portion comprises a member depending from said fitment shaped and dimensioned to engage said fitment engaging portion.
 48. A method according to claim 47 in which said member is a ring.
 49. A method according to claim 48 in which said ring depends from said flange.
 50. A method according to claim 48 in which said ring depends from said membrane.
 51. A method according to claim 50 in which said ring is hooked in cross-section.
 52. A method according to claim 48 in which said ring is interrupted.
 53. A method according to claim 47 in which said membrane comprises a plurality of vertically disposed fingers.
 54. A method according to claim 59 in which said fingers are hooked.
 55. A method according to claim 47 in which said member comprises a stud depending from said membrane
 56. A method according to claim 47 in which said member comprises a ring depending from the periphery of said flange. 